The present invention relates to a method of fabricating a leading edge shield. Such leading edge shields are typically for protecting the leading edges of rotary blades against impacts. In this context, the term “blades” should be understood to cover both fan blades and aerial propeller blades. In order to limit their weight, these blades are typically made of composite material comprising a polymer matrix reinforced by fibers. Although such materials present mechanical qualities that are generally very favorable, in particular relative to their weight, they are highly sensitive to point impacts, which can specifically lead to phenomena of delamination within the material. Shields, typically made of very strong metal materials such as titanium alloys, are therefore normally installed on the leading edges of such blades, in order to protect them against these impacts. Such shields are normally in the form of thin pressure side and suction side fins that are joined together by a thicker section overlying the leading edge, the shield as a whole matching the shape of the blade on its leading edge and on its adjacent pressure side and side sections. The pressure and suction side fins extend over these sections respectively on the pressure and suction sides of the blades, and they serve mainly to ensure that the shield is positioned and secured to the leading edge.
In order to improve the aerodynamic performance of blades, their leading edges present shapes that are ever more complex, thereby complicating the fabrication of shields that need to match these shapes. Two methods are presently known to the person skilled in the art. In a first of those methods, the shield is fabricated mainly by forging starting from a bar of alloy, with successive steps of cambering, filling, and extrusion, and with a final twisting step in order to move the fins towards each other and calibrate the thickest section. Applying that first method of the prior art to materials that are as strong as the titanium alloys typically used for leading edge shields nevertheless presents major drawbacks: a high level of wear for forging tools and a large number of fabrication steps, which is economically unfavorable, and great difficulty in obtaining very small thicknesses for the fins or small transition radii between the fins and the thicker section, which is technically inconvenient.
In another prior art method, the shield is made from sheets that have been machined in order to form thicker regions prior to shaping the shield. Nevertheless, that prior machining presents the drawbacks of wasting a large amount of expensive material, and also of subjecting the machining tools to wear and of requiring a long time for machining.